Older women of low socioeconomic status (SES) have higher prevalence of cardiovascular disease (CVD) than older women of high SES. This difference, a source of disparity in mortality and disability, is not explained by traditional CVD risk factors. Despite recent policy emphasis on health disparities, the Contributing biological mechanisms are largely unspecified. Differential stress experience between SES groups could affect CVD disparities. Allostatic load is a single parameter that represents the sum of multiple body system indicators and is theorized to be a cumulative measure of stress-related biological risk. The purpose of this study is to test the hypothesis that allostatic load is a mediator between SES and incident CVD in a population of older women. The study will use data from the Women's Health and Aging Study 2, a 10 year longitudinal study of 436 women aged 70-79 years old at baseline. The socioeconomic diversity of the subjects and the range of biological data provided are ideal to test the candidate's hypotheses. Employing the theory of allostatic load in a sample of older women of a wide SES range may provide important insight into mechanisms contributing to the significant problem of health disparities in CVD.